Hybrid energy systems often include a primary energy source (e.g., one or more generator sets) that is coupled to a load. During certain operating conditions (e.g., high-speed low torque), the primary energy source meets all of the energy requirements of the load, but during other operating conditions, the primary energy source may be insufficient to satisfy increased load demands with a requisite transient response. For example, an operator or a load may require more energy than the primary energy source is capable of outputting at a given time. Accordingly, hybrid energy systems may include an energy storage device to provide additional energy to the load when engine output is insufficient to meet a desired transient response or may include an energy consumption device (load bank) to manage the average load to meet a desired transient response. There is a conflict, however, between providing an energy storage device that has a sufficiently high capacity to meet contemplated transient response needs and minimizing manufacturing costs. That is, the larger the capacity of the energy storage device, the higher the manufacturing cost.
U.S. Pat. No. 8,190,299 (“the '299 patent”) issued to Rovnyak et al. discloses an energy control system and method to improve engine transient response. Rovnyak et al. employ feedback and control to respond to a sudden increase in load demand and corresponding drop in engine speed. Rovnyak et al. respond to such an increase by increasing the engine throttle angle. The increased throttle angle will cause engine speed to return to a desired set point faster than it would otherwise.
Although the methods of the '299 patent may improve the transient response of an engine, the '299 patent does not address how to improve the transient response of a hybrid energy system. Further, in a hybrid energy system, the energy storage device may be used to supplement the primary energy source to produce a desired response. The method employed by Rovnyak et al. does not address how to minimize the output of an energy storage device in a hybrid energy system while maintain adherence to transient response requirements.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above.